1. Technical Field
The disclosure relates to a display device and driving method thereof, and more particularly, to an autostereoscopic display device having touch sensing mechanism and driving method thereof.
2. Description of the Related Art
In recent years, various stereoscopic display modes have been developed to make an observer obtain stereoscopic sense, which is achieved by providing different images individually to the left and right eyes of the observer so that the brain of the observer is able to analyze the overlapping images and identify the depth and gradation of each component to obtain stereoscopic sense. In general, stereoscopic display devices may be classified into passive stereoscopic display devices and autostereoscopic display devices. While using a passive stereoscopic display device, the observer should wear certain assisting equipment, for example, polarization glasses or shutter glasses. However, while using an autostereoscopic display device, the observer is not required to wear any assisting equipment because separated images for obtaining stereoscopic sense are provided by a build-in image separation panel thereof, making application of the autostereoscopic display device increasingly widespread. Besides, along with the requirement of a friendly communication interface for a user to interact with an electronic device, a touch-sensitive display device for controlling operations of the electronic device, instead of using a keyboard or a mouse, has steadily become the mainstream. The touch-sensitive display device may employ a resistive touch panel or a capacitive touch panel to sense touch inputs. The resistive touch panel locates touch input positions through voltage drops, but is unable to provide multitouch input functionality. The capacitive touch panel typically includes sensing capacitors, and performs signal processing on capacitance variations of the sensing capacitors corresponding to touch points for locating touch input positions, which is able to provide multitouch input functionality, thereby gaining increasing popularity.
In view of that, the autostereoscopic display device having touch sensing mechanism normally includes an image separation panel and a capacitive touch panel attached thereon. The image separation panel has a substrate, a counter substrate, a liquid crystal layer sandwiched between two said substrates, a first electrode disposed on the substrate for receiving a first control signal, and a second electrode disposed on the counter substrate for receiving a second control signal. The polarity of the first control signal relative to the second control signal should be inverted periodically for protecting the liquid crystal layer from causing permanent deterioration due to polarization. Regarding the prior-art method of driving the image separation panel, while the first control signal is switched from a first low voltage to a first high voltage in a rapid-shift manner, the second control signal is switched from a second low voltage to a second high voltage in a rapid-shift manner. In order to provide the polarity inversion operation for protecting the liquid crystal layer, the first low voltage is less than the second low voltage and the first high voltage is greater than the second high voltage, i.e. the first and second control signals are in phase with each other. Accordingly, the first high voltage is much higher than the first low voltage, such that the sensing operation of the capacitive touch panel is likely to be seriously interfered by an occurrence of transient alternating electric field resulting from the switching of the first control signal, which may incur a touch misjudgment event due to an error output signal of the capacitive touch panel and, in turn, results in malfunction of backend circuit.